1. Field of the Invention
This invention relates to reusable pipe fitting plugs for temporarily sealing an open hub of a non-threaded female pipe fitting.
2. Art Relating to the Invention
Reusable pipe fitting plugs provide an inexpensive means to control the unwanted release of fluids or air from an open pipe connection. Reusable pipe fitting plugs can also be used to isolate various sections of a pipe system during construction or maintenance.
Conventional reusable pipe fitting plugs are designed with an expandable rubber sealing means that is capable of forming a watertight seal between the pipe fitting plug and the inner surface of the pipe fitting hub.
In a typical design, the pipe fitting plug is shaped as a cylinder with a diameter of slightly less than the diameter of the pipe fitting hub that is desired to be plugged. The pipe fitting plug therefore covers the majority of the diameter of the inside of the pipe fitting hub. The expandable rubber sealing means is provided along the circumference of the pipe fitting plug and is capable of filling the gap between the outside of the pipe fitting plug and the inside of the pipe fitting hub. Fluid flow is restricted upon the plugging of the gap with the rubber sealing means.
Conventional pipe fitting plugs have a rubber sealing element located within a recess of the cylinder. A tightening means is designed to exert a force through the body of the pipe fitting plug so as to decrease the recess and expand the rubber sealing element. The rubber sealing element expands under the pressure exerted by the tightening means to form a watertight seal between the pipe fitting plug and the pipe fitting hub.
One of the drawbacks of conventional pipe fitting plugs is that they can only withstand a limited fluid pressure. When the fluid pressure against the pipe fitting plug passes a threshold value, the rubber sealing element can no longer hold the pipe fitting plug in place and the pipe fitting plug is forced out of the pipe fitting hub. This is known as plug blow out, and results in uncontrolled flooding and damage.
Further, debris, dirt and solvent may be deposited within the inner surface of the pipe fitting hub causing slippage between the rubber sealing element and the pipe fitting hub resulting in further undesired consequences.
It is therefore desirable to obtain a reusable pipe fitting plug that is capable of withstanding increased fluid pressures and soiled surfaces without becoming disengaged from the pipe fitting hub and causing flooding.